Symmetry in Paraspinal Muscles as a Predictor of the Development of Pregnancy-Related Low Back and Pelvic Pain: A Prospective Study.

OBJECTIVE: To determine the asymmetry in the paraspinal muscle before pregnancy and evaluate its association with pregnancy-associated lumbopelvic pain (LPP). METHODS: This was a prospective case-control study conducted from January 2017 and December 2018. A total of 171 subjects (mean age ± SD, 27.4 ± 5.8 years) were finally divided into the LBP group, PGP group, and no LPP group. Each subject was asked to follow a standardized clinical imaging protocol before the pregnancy. The area of muscles (multifidus, erector spinae, and psoas muscles) on the axial slice at mid-disc of L4 -L5 and L5 -S1 were segmented and then the cross-sectional area (CSA) of a particular muscle was measured by outlining the innermost fascial border surrounding each muscle. The mean value of F-CSA's ratio to T-CSA (F/T CSA) was used to determine whether the bilateral paraspinal muscle was asymmetrical. Total muscle CSA (T-CSA) represents the sum of CSA of interested three muscles. The signal intensity can distinguish fat and muscle tissue in a different range. Based on this, functional CSA (F-CSA), represented by fat-free area, was evaluated quantitively by excluding the signal of the deposits of intramuscular fat. Total muscle CSA (T-CSA), functional CSA (F-CSA), and the ratio of F-CSA to T-CSA (F/T CSA) were measured unilaterally and compared between groups. Logistic regression was performed to determine the risk factors for pregnancy-associated LPP. The Pearson correlation coefficient was performed to test the relationship between asymmetry in F/T-CSA and pain rating. RESULTS: A total of 124 subjects (72.5%) (28.5 ± 5.2 years) had LPP during pregnancy. Forty-eight (38.7%) individuals had low back pain (LBP) and 76 (61.3%) had pelvic girdle pain (PGP). Seventy-six women (44.4%) were determined to have asymmetry in paraspinal muscle according to the definition in this methods section. The duration of follow-up was 24 months postpartum. A total of 39 (31.5%) women unrecovered from LPP. F/T-CSA was significantly decreased for LBP in the PGP group than in the and control group (0.03 ± 0.02 vs 0.05 ± 0.03 vs 0.12 ± 0.05, P < 0.001). Meanwhile, significant differences were detected in both groups (all P < 0.001). In patients with LBP, the level of paraspinal asymmetry, represented by the difference in F/T-CSA, was positively correlated with pain scores (r = 0.52, P < 0.01). However, no statistically significant correlation between pain scores and paraspinal asymmetry was found in PGP (r = 0.42, P > 0.05). Asymmetry in the paraspinal muscle (adjusted OR = 1.5), LBP (adjusted OR = 1.6), LPP in a previous pregnancy (adjusted OR = 1.4), sick leave ≥90 days (adjusted OR = 1.2), and heavy labor (adjusted OR = 1.2) were risk factors for the unrecovered LPP during pregnancy. CONCLUSIONS: Asymmetrical muscular compositions could lead to abnormal biomechanics for the segmental motions. Lateral-directed physical training and stretching may help decrease the occurrence and severity of this condition.

Stretching Force of Incision Affects Early Clinical Results After Primary Total Knee Arthroplasty: A Retrospective Study.

OBJECTIVE: To investigate the impact of different skin incisions on recovery from total knee arthroplasty (TKA). METHODS: This is a retrospective study conducted in a tertiary hospital. A total of 1210 patients accepted primary and unilateral total knee arthroplasty (TKA) at the authors' affiliated institutions between January 2015 and January 2019. Patients who accepted primary and unilateral TKA due to OA under epidural anesthesia were included. Excluded cases included patients who had no completed follow-up; preoperative flexion contracture greater than 15° and preoperative flexion less than 90°; paresthesia in lower limb; scar within the knee area; patella alta or baja. We recorded and analyzed the following data, including each patient's characteristics, incision stretching index (IS index), perioperative information, and follow-up assessments. Patients were grouped by trisecting the range of IS index we observed in the present study. The primary outcome measure was the visual analog scale (VAS) pain score rated on a scale of 0-10 from no pain to severe pain. Secondary outcome measures include knee girth reflecting postoperative swelling, knee range of motion (ROM), sensory testing, and the strength of quadriceps. These measures were completed 2 weeks postoperatively. RESULTS: A total of 1089 patients undergoing primary and unilateral TKA in our two institutions were screened for final analysis, and 121 ones were excluded. The patients were followed up for an average of 13.3 months postoperatively. The mean length of FL was 28.3 cm (range: 21.0-38.8 cm). The mean IS index was 2.7 cm (range: 0.4-5.1 cm). We found no significant difference in those data among groups (P > 0.05). VAS pain scores among group IS A, IS B, and IS C were significantly different (2.3 ± 0.6 vs 3.4 ± 1.6 vs 3.9 ± 1.5, P = 0.0001). Similar situations were seen in knee circumference, ROM, area of abnormal sensation, and quadriceps strength among groups (all P < 0.05). With the increase in the IS index, VAS pain score, knee circumference, area of abnormal sensation, and incision problems were significantly increased (P < 0.05). At the same time, ROM and the strength of quadriceps decreased (P < 0.05). With the increase in the IS index, the number of patients with incision problems was increased significantly (P < 0.05). Besides, no significant difference in PJI and DVT among groups was observed (P > 0.05). CONCLUSIONS: Proper incision stretching can improve postoperative pain relief, surgical swelling, ROM, sensory disturbance of the knee, and the strength of quadriceps with reduced risk of incision complications.